Variable-speed motor.



A. A. PIPER.& 0. E. F. AHLM.

VARIABLE SPEED MOTOR. APPLIOATIOI rnnn 23.14. 190a.

Patanted 001;.6, 1908.

2' SHBETFBKEET 1.

1116610 tOTS; Mil-18'. lam

a e a 0 e n i m Hi/W A. A. PIPER & c. E. F. AHLM.

VARIABLE SPEED MOTOR.

APPLICATION FILED P3114, 1906.

900,420; Patented Oct. 6, 1908.

Y Cmnnns 'E. F. AHLM UNITED STATES PA ALVIN arisen AND CHARLES E. F. AHLM ASSIGNMENTS, TO F. B. WAGNER, F CL OF OLEVELAN 1), 01110, assioi'oas,

BY MESNE EVELAND, OHIO.

VARIABLE-SPEED MOTOR.

Speciflcation of Letters Patent.

Patented Oct. 6, 1908.

Application filed robust- 14, 1906. Serial No. 800,983.

To all whom it may concern." Be it known that we, ALVIN A. PIFER and both citizens of the United States, and both residing at Cleveaha, in the county of Cuyahoga and State of Ohio, have invented a certain new-and useful Improvement in Variable-Speed Motors, of

' which the following is a full, clear, andexact .phshi magnetic shunt and divertin some of the noted. This sp description, reference companying drawings.

Our'invention relates to dynamo electric machines, and itsobject is to providg means whereby the speed re lated as desired.

he regulation of the speed of a d 'namo electric machine may be acoomp'lis ed in several different ways, to all of which it is not here necessa to refer in detail; but,

own for accomof employinga being bad to the acng this purpose is that lines of force from their norma path through the arm ture. One of the specific adaptations of rinciple has been the use of a single iron p ate adapted to be moved between the armature and each pole of the field magnet, 'so as to fill the space between the pole piece and the armature. Such a plate serves as a deflector for the magnetic flux when moved to one side, and in this way operates under the general principle before ecific structure is, however, open to objections which have prevented it comin into general use, and which havebeen the sugiject of attention on the part of subsequfintlinventors who have succeeded in overco 'ng certain of the disadvantages; but at the cost of complexity of structure. One of the chief disadvantages attendingthe use of this specific machine was the consequent shifting of the "neutral line", or'the'oretical diameter of commutation, in the magnetic field, which is normally midwa between the adjacent pole pieces. This ifficulty was eventually remedied to a degree by an arof the machine may be angular dislocation of the neutral lines did not, in fact, advance to the same angular extent as the movable plates the shifting of the commutator brushes did not satisfactoril' remedy the difficulty. The structure whic we-have devised overcomes the above noted defects and possesses advantages not hitherto obtainable.

Referring-to the accompanying drawings, Figure 1 1s an end elevation with parts broken away showing our construction of -Wsriable speed motor. Fig. 2 is an end elevation of our variabl speed motor partly in section in order to better show the construction, and showing the pole-shoesections moved so as to divert the magnetic flux. Fig. 3 is a transverse section on the lines 44 of Fig. 1. Fig. 4 is a detail.

In the form of machine illustrat frame A of the motor su pieces B, thecoils, B, for w ich are rctalned in position by brackets A secured to the frame. At the inner extremity of each pole piece,next to the armature C, we provide two pole-shoe sections D, D, w 'ch are secured to and'supported by rotatable diamagnetic rings E, E. It will be noted that each shoe section is secured at one side to one ring, and guided by tongue and groove connection with the other ring. f

The alternate shoe sections are screwed to the same ring and each is rotatably mounted in ways A on the brackets A so that they can be shifted' an larl and retained in pro er position. T e po e-shoe sections difer mm the single plates hitherto used in the art in that, whereas the said single plates were constructed to be moved between the armature and the pole -of the magnet, our pole shoe sections are constructed so that they cannot move but half-way between, a

ed, the ports four pole rangement of mechanism whereby the'conimu tator brushes were shifted simultaneously and to the samefld' 'ee'with the shif of the iron plate. Suc sh'lfting was seen and the, brushes with the result an the br'u'sh fi'wero same a 15 PWYQ QQ e connectionfiietwe'enthe movable late p construction which has advantages as will be set forth below. It will be'seen that movement' of the is absolutely independent of the pole pieces, since the ringsand'sections are not supportedfrom or connected with'and do ngage the pole cor'esin an manner.

ort u so of sh' the rings, we provide eac o them'with i im segmental rack on the periphery. Journaled in the ame in-ah'y suitable manner "an'e'two short and the pole-shoe sections not - shafts" E carrying respec tively', eacliin' osition-to mesh-with one-of theracks on t e EB. At one", end shaftsare each provided with pinionsiE which. intermesh' so" that the rotation 'ofone shaft in either direction'will causethe other shaft .to rotate 'in the op site direction. Thus, as will be evident, a smglehand' wheel fitted to either shaft E E can'be used shifting allof the pole shoe sections. 'Assu' the part to be in-the positionsho wn inlii 1-, the rotation of'the. shaft in the proper irection will cause the several shoe sections to-gradually assume the pesition shown in :Fig. 2. Asthis movement takes place-the magnetic flux will be'slmnt'ed I i so as-to decrease the number of lines of-iorce passing through the armature and an air-ga piece, thus the'magnetic reluctance at that point. The combined'efi'ect of the? shifting of the shoe sections, so as to shunt the lines of force, and the creationof an air gap atthe centerof the pole-pieces is to cause a weakening of the magnetic field, the

strength of. which may obviously be regulated with any desired fineriessand without loss of energy; V

The increase of the magnetic reluctance about the center of the pole ieces will cause.

the crowding of the lines of orce toward the edges of the-pole pieces,--and thus increase the density at'the latter oints so that the den er of sparking, whic is resent when the %eld is weakened at the e es, is eliminated, Further, it'will be note 'that as the several oleshoe sections approach the'adj acent shoe sections the do so in a uniform manner, and maintain t e diameter of commutation inan absolutely constant position, regardless of any amount of angular change upon'the part of the sections. "The advan-" tage of thisconstruction will be obvious to those skilled in the art: While-in the positions of the tion shown in Fig. 3, the number of linesof force passing throughthe armature will be reduced to a minimum and the magnetic field weakened to the greatest extent desired, with the result that a motor will not race under a decreased load. a This degree of 0on trol or speed regulation may be adjusted to any extent necessary bythe mere turningof the shaft which carries the pinions meshing with the segmental racks u on-the diamag-' netic rings car the po e-shoes. Upon the shifting of the nngs in the opposite direction to that just described the divided sec ole-shoes-will again .come to-; ether and t e air t us restoring the in netic field. Having thus described our invention,-we claim:

L A regulator for a dynamo electric mal strength of the mag-..

for

gap will be eliminated,

cifine comfising two pcfieshoe section adapted to moved-from andtoward each other, the centenof each section movi axes'of t e pole pieceso the'machiiie,

2,- 'A'regulator fora dynamo electric machine do 'rising-two separate and independen't.pole=s oe sections adapted to be moved toward from each other and circumferentiallv aboutth'e armature, thecenter. of each section moving-substantially in the plane ug ..the axes of the pole pieces of .pass' thro .the n il chineL -.3.- A; regulator for dynamo electric ma chinery. comprising two separate pole-shoe sections a'da ted to be moved toward and from each 051 means for causing such movement to be siniultaneous and of the same angular extent.

5. A regulator for dynamo electric .macbinery comlprising two sup orts each carrying pole-s 0e sections, an means-for simultaneously moving said supports so that cede fromeach other, the center of each secsubstanuall infthe plane fpassing throng the b8 eag e centefi of 1each section su llihnti t e'l 'ane assin will be formed at the center of each po 0; h p p g a said sections maybe made to approach or re tion moving substantially in the plane passing through the axes of the pole pieces of the machine.

6. In a dynamo electric machine, the combination of an armatureffield magnet polepieces, bracket supports projecting from the machine frame, n s mounted on said brackets, and pole-s oe sections secured to said 7. 'Ina dynamo electric machine the combinationof an armature, field magnet polepieces, bracket supports pro'ecting from the -machine frame, rings rotata 1y mounted on .said brackets,.' and ole-shoe sections each secured toone of sai rings, the alternate sections being secured to the same ring.

8. A dynamo electric machine comprising a plurality of field magnet pole pieces arranged circumferentially about thearmature a single series of pole-shoe sections, tworotatable supporti rings concentric with the armature, each a ternate and only each alter nate member of the series of shoe sections secured to the same ring.

9 A dynamo electric machine comprising a plurality of pole pieces disposed circumferentially about the armature, a series of. poleshoe sections, two rotatable supportingrmgs one ring secured only a series, the other secured to and onfy to the other section of t e series, and. means for dis laei the rings singularly, simultane- 5 ous y an to the same extent in opposite directions.

In testimony whereof, we hereunto affix ALVIN A. PIFER. CHARLES E. F. Al-ILM'. Witnesses:

J. M. WOODWARD,

E. B. GILCHRIST.

to alternate sections of our signatures in the presence of two \vit messes. 

